The Aerodynamics of Tube Travel-Effects of Compressibility and the Resistance of Slender Cylinders Traveling in a Tube

摘要

Slender-body theory is used to determine the flow about a slender body of revolution traveling inside a tube at subcritical speed in a compressible fluid. It is shown that if the tube diameter is a small percent of the body length and the body is centered in the tube then the axial component of the flow in the annular region between the body and the tube can be approximated by one-dimensional compressible channel flow. Formulas for all the static and dynamic stability derivatives are derived for an arbitrary body of revolution in terms of its cross-sectional area distribution. The dynamic derivatives are shown to be identical with their incompressible counterparts. The static derivatives, on the other hand, are Mach number dependent and, as an illustrative example, these are calculated for an ellipsoid, and the results are normalized with respect to their incompressible counterparts. The resulting compressibility rise is presented graphically as a fun ction of the ratio of the maximum cross-sectional area of the body to the area of the tube for various free-stream Mach numbers. The augmentation factor due to the presence of the tube walls, which had previously been calculated for incompressible flow, is shown to be augmented still further by the effect of compressibility. (Author)